Brake tester for motor vehicle wheels



Nov. 22, 1932. STRQUD 1,888,639

BRAKE TESTER FOR mowon VEHICLE WHEELS Filed July 3, 1929 4 Sheets-Sheet i avweutoz RH fiz z'oud.

as Z

/ attozwwo Nov. 22, 1932. TRO D BRAKE TESTER FOR MOTOR VEHICLE WHEELS Filed July 5, 1929 4 Sheets-Sheet 2 .3 H fll f'o "Lac!- Nov. 22, 1932. F. H. STROUD BRAKE TESTER FOR MOTOR VEHICLE WHEELS Filed July 3, 1929 4 Sheets-Sheet a 1 RH 951% ad.

a 1 1 I y flfiozwm o E Pr/z/N F. H. STROUD 1,888,639

BRAKE TESTER FOR MOTOR VEHICLE WHEELS Filed July 3, 1929 4 Sheets-Sheet 4 17% SZ Z'ozLJ.

%9 abto'onwo Patented Nov. 22, 1932 li,888,639f

rnnncr'sn. sTnoUD, pr SEATTLE, wAsnInGTon; AssIenon TooEO GE wILmonT J eRA Tz; or SEATTLE, wAsnING oN 1BRAJKE T STER FOR MOTOR vnmcmwmms Application filed J'uly 1929. A ain no; 375,671.

The present invention is directed to improvements in brake testers for motor vehicle wheels. Y V The primary object-of the invention is to provide a device of this character so con structed that the vehicle can be driven uponr accurate the units of the device to obtain an reading as to the braking resistance Another object of theinvention isto pro 1 *vide' a device of this kind including four independent units soarrangedthat a vehicle equipped with either two or four wheel brakes can be tested.

Another object of the invention is to provide a device of this kind so constructed that the braking action of individual wheels can be ascertained in order that adjustment can be made to overcome any inequalities of the V brakes. Y I Another and important object of the invention is to'provide a brake tester wherein the.

indicating pointersmust bereturned to their normal or inoperative position by hand after] each testing operation.

invention resides in the novel features of con struction, formation, combination and ar rangement of parts to be hereinafter more fully, described,clairned and illustrated in the A accompanying drawings, in which Figure 1 is a plan view showing the rela-.

tive' arrangement of the units. i

Figure 2 is a plan view, partly in section,

n ofone of the units.

Figure 3 is a longitudinal sectional view' the sameforwardly, the shock being absorbed therethrough.

Figure 4 is a sectional viewon the line 4-4 of Figure 3. j p a Figure 5 is a sectional View on the line 5-'5 of Figure 2.

Figure 6 is a sectional view on the line 6'6 of Figure 5. a

Figure 7 is a plan" view of the indicator arm in its released position. As shown in Figure 1, four units Aare employed, one for each wheel of a vehicle when equipped with four wheel brakes, and" since each unit is identical in construction,

a description of one will suifi'ce for all.

Each 'unitincludes'a foundation 1 in which tween the channelmembers 3.

With theseand other objects s w, this of the is formed a pit 2 and in which is supported a pair of parallel spaced channel members 3 for-supporting the anti-frictiomrollers 4.

A sheet metal platform 5 is provided and is preferably coated with a layer 6 ofcement, said platform having channels 7- 'formedf in 7 its under surface for cooperation with the:

rollers 4 in order that the platform .can'roll w when subjected tothe resistance ofthe vehicle wheel. Abracket 8 depends :fromthe' platform 5 and has threaded therein the front end of a rod 9, :the rearend thereof having' a piston 10 movable in the cylinder 11,"said cylinder being rigidly supported by and be- The rear wall l2 of the cylinder is provided with vents13 so as to release the pressure as the piston travels oniits rear. stroke. y

A head 14 is supported in the forward end of the pit 2 anda coil spring 15 is interposed between said head and the bracket 8 so as toresist the forward travel of the "platform.

The spring extends'parall'el with the direc-l f tion of movement of the platform.

The front end of the pit isoverhung'by a tread-plate 16 underwhichithe forwardfend platform travels When moving forv I w rdly. 1i,

I A plate 17 normally overlaps the rear end of the platform 5 -so that a wheel can eon: veniently' roll upon the platform when the device is in operation. I

It will be obvious that-When awheel rolls upon the platform. and the brake is applied, the drag thereof upon the platform will shift by the' spring 15, which also servesto move the platform rearwardly afterlthe wheel has passed over the platform, the speed of the rearward movementof the platform being governed by the" piston moving rearwardly in the cylinder'11. a v V To'one side of each platformis fixed a bracket 18,;having a pin19 carried thereby for engagement in a slot- 20' formed-in the horizontal arm 21 fixed to the vertical shaft'22,"the upperend of which 1 extends into the register casing 23 supported by. a standard 24. 1 The bottom wall ofthe" if casing has markedthereon suitable gradua the lower end of I 1 therein.

"rested and it returns tonormal position. the frictionalrengagement between the head of;

through an arcuate sight opening formed in the top wall of the casing"; The top wall of the casing has formed upon its undersurface an arcuate r1b'26 and a stop pin 27, the

purpose of which will be later explainedhead 28 is rotatably engaged in the oas- A I ingand has a socket 29 formed therein for rotatably receiving the upper end .of the shaft 22, said head having a slot 30'formed; Formed integral withthe head 28 is an arm to facilitate rotation thereof.

The arm-31has a bearing 34 in which is engaged a pin 35 having a head 36 for en- Q'ofgagingthe rib 26 A leaf spring 37 is pro videdand has one end fix'edto the arm and the pin-35 and serves .frictionally engaged with the, rib 26. l Pivzii otally connectedfto the pin 35fis a detent'38,

the free 'endfof which extends through the slot30 and'is adapted to engage the notch 38,formed in the upper, end of the shaft 22.

In. order to j normally hold the detent en so gaged in the notch 38 aispring 39-is provided and has one end anchored, as at 40, in the arm," and its other end provided with an extensional for. engaging one sideof thedetcnt 37., This spring normally serves 'to hold the detent'ymldably' engaged with the'stop pin 27. j V, Briefly, the operation is as. follows:

7 A units and stopped beyondi them; As the 4o" 'wheelsjencountertheplatforms 5,,the brakes arejappliedto-arrest themovement of the" car. 'gThe wheels will then'roll'upon the plat forms if not locked, or slidethereon if locked,

whereupon the 'dragiof the wheels upon: the

"platforms will shiftthesame forwardly, such action causing the brackets 8 to compressthe springs 15 and move'the pistons 10 forwardly:

in .thecylinders; As each platform noves 7 forwardly, the shaft22, through the medium a "of the arm 20, will rotate,

' is engaged in thenotch and since the detent pointer 32 will swingoutwardly and dragthehead 3610f the pin 3 over therib 26. When the forwardmovement of the platform is arthe pin and the rib will be sufficient to hold the pointer 32 in registration with the graduation 'B,'.thus denoting the brakeaction. V As soon as the readingis obtained, the knob 33 is'grasped and the head 28 turnedto swing the arm 31 and pointer 32 to reset. position. Atthistime, the shaft 22has been rotated to cause disengagement of :the. detent 38 :from

i the notch 38- whereupon the-spring 3Qswings 31 having a'p'ointer 32 fixed to its j outer end for coaction with the graduations. B upon the bottom wall of the casing 23. The

;- head; 28'has a knob 33 upon its upper end 5 mounting the platform, 7 a bracket depending therefrom, The car toybe tested is driven across the:

38, the arm 31 and the detent to the position shown in Fig. Reverse movement of the platform 5 will reverse the movement of the shaft 22 in order that the notch 38 will be properly positioned for again engaging the detent upon turning the head. As the head is turned manually,'the

arm 31 swings inwardly,"duringlwhich the detent engages the stop pin 27 to swing; ngagem w t e. q t I will be apparent thatthe shaft 22 rotates a" distance corresponding to the dragof the Lwheel (with brake set) .upon the, platform,

the same into andthat the tensionof' the spring 39 is sufficient to swing thedetent from engagement I with the notch 38 Since it is necessary tojzreturn the point ers to their reset or normal position by hand, 7 after each testing operation, and beforethe device will again register-,f=the travel of the rear wheels over the forward platforms will in nowaydisturb the pointers operatedthere-i i its free endengaged withthe lowerend: of b 1 c tohold the head shape, proportion and minor details or construction may be resorted to without depart; ing from the spirit or. sacrificing any of the advantages of the invention. 1

'jWhat is. claimed is .2'

1. A brake tester for vehicle wheels 05m. 7

prising a platform, means 1 ;-for slidably and it will'b'e understood th'at various changesin size,v

A From theforegoing, it .is 'thoughtthat-: the construction,operation andsm'anyad I r said platformhaving a headad-ljacent the bracket,a coiled spring interposed between thehead and bracket andextending parallel with th'efdirection of movement. of

below the platform,- an aircheckipiston slid-i;

able in the cylinder, a rod connecting'thei;pis ton and bracket, said spring serving to resist movement of the platform 'in' onezd-irectionr when subjected to. the fdrag of'a wheel' with set brake passingv thereover, saidpistonserving to: retard; the movement of the: platform by said spring in a reverse direction, aregister includln g apo1nter'and' a casing provided with graduations, connections between the J platform and pointer for actuating the pointer upon movement of the platform'by the" v tionafter'eachactuationthereof,

2. A braketester forve 'clefwheelscom -.5

prising a. pl-atf0rm, means f0r slidably supporting the platform, a brackebextending downwardly from the platform, a stationary;

head below the platform, a helical spring-n11 terposedibetween the head "and thezbracket. and extending parallel withthe direction: of

9.5 the platform, 'a'oylinder mounted stationary.

movement .of the platform for resisting a forward movement of the platformwhen subjected to the drag of a wheel passing thereover with set brake, a stationary; cylinder below the platform, an air check piston in the cylinder operatively connected to'thebracket for resisting movement of the platform in a 7 reverse direction by expansion of said .sprlng,

a shaft, a connection betweenthe shaft and platform forrotating the shaft upon movement of the platform, an arm pivotally connectedwith the shaft, a casing for the shaft having graduations, a pointer carried the shaft for cooperatlng with said graduations,

a detent pivotally associated with the arm and normally engaged in a notch in the shaft for swinging the arm and pointer upon rotation of the shaft in one direction, means for disengaging the detent from the notch in the shaft upon reverse rotation of the shaft, and cooperative means carried by the arm and casing forholding said arm' and pointer against reverse pivotal movem'entupon reof the platform, means' for opposing eXpansion movement of said spring, a casing mounted adjacent the platform and having graduationstherein, a shafteXtending into the casing, means connecting the shaft and platformfor rotating the former uponlongitudinal movement of the vplatform in one difrictionally engagedwith the rib, a detent Y pivotally connected with the pin and having its free end adapted tojjdetachably engage j; v

the notch, said detent serving to swing the arm andpointer uponrotation of the; shaft,

and resilient means'for disengaging the detent from'the notch upon rotation of the" against'reverserotation. a 5. A braketesterforvehicle wheelscom able in one direction under the action "of a 1 wheel with set brake passingthereover, a

bracket carried by theunderneath"face of '1 the platform, a'stationary headtopposite said bracket, a helical spring extending parallel iwiththe direction ofmovement of said platform andid'isposed atthe longitudinal axis of said platformgbetweensaid head'and said N bracket, movement of said bracket serving to compress said springfajstationary cylin 'der' on theopposite side 'of saidbracket from said head, a movable air check piston in said cylinder having a piston rod fixed to said bracket whereby said; piston opposes moveshaft, said pin serving tohold the arm a 76 prisinga slidably supported platform ,mov-

ment'ofsaid spring in onedirection under' the impulse of saidfwheel and returns said platform without shock to-no'rmal position under .action of expansion of saidfspring,"

and a registering device operatively connect-' ed with the platform and indicating, movement'thereof under impulse of said wheel.

In testimony whereof Iafiix'my signature.

FRANCIS STBOUD. [us] i 1 rectionwhen subjectedtothe drag of awheel, V i l Q an arm pivotally connected with-the shaft and having a pointer connected thereto for cooperation with thegraduations, a detent pivotally connectedwith the arm and having one end detachably engaged in a. notch in the shaft, saidideten't serving'to swing the arm and pointer in one direction upon rotation of the shaft, and means for frictionally holding the arm in itsshifted position upon the reverse rotation of the shaft.

4. A brake tester for vehicle wheels comprising a slidably supported platform movable inone direction under the action of a 7 wheel with set brake passing thereover, a

bracket carried by the platform, a spring adapted to be compressed by the bracket, a cushion device opposing expansion move- V ment of the spring, a register including a casing, said casing having a rib therein, a shaft extending into the casing, connections between the shaft and platform for rotating the shaft upon movement of the platform in one direction, an arm rotatably engaged with the shaft and having a pointer carried thereby,

said shaft having a notch therein, a pincarp ried by the arm and having its head engaged with the rib, means for yieldably holding the x 

